SCOAR Model

Scripps Coupled Ocean-Atmosphere Regional (SCOAR) Model

Hyodae Seo (hseo@whoi.edu)

Seo, H., A. J. Miller and J. O. Roads, 2007: The Scripps Coupled Ocean-Atmosphere Regional (SCOAR) model, with applications in the eastern Pacific sector. J. Climate, 20, 381-402
Seo, H., A. C. Subramanian, A. J. Miller, and N. R. Cavanaugh, 2014: Coupled impacts of the diurnal cycle of sea surface temperature on the Madden-Julian Oscillation. J. Climate, 27, 8422-8443

Key features

• The SCOAR model is portable, which is designed to be applied to different geographic regions and under different climate regimes, making it an ideal tool to study process-modeling of coupled air-sea interactions.
• The coupler also should conserve mass and energy. This is achieved with the most use of the individual model physics to calculate the variables for coupling (i.e., atmospheric surface forcing from the atmospheric nonlocal boundary layer physics), which also ensure consistency in flux between the ocean and atmosphere.
  
• The SCOAR coupler is an input-output based file coupler. One of the disadvantages of the file-coupling is that the coupler can be computationally inefficient if re-gridding of fluxes and SST on a large grid size has to be involved at high coupling frequency. In the past applications, the SCOAR coupler has shown to be very efficient (typically <5% of CPU total wall-clock hours). The efficiency in coupling is also aided by choosing the identical model grids in the ocean and atmosphere, which helps to maximize the effect of air-sea coupling given the simulated fine-scale SSTs by the ocean model, (Seo et al. 2008b; 2009; 2014; 2015). It also eliminates the known issue of regridding wind near the steep orography and complex coastlines.

• Unlike many currently available regional coupled modeling system applied to the climate studies, SCOAR, one of its first kind, is based on a very simple input-output coupler. This file-coupling strategy becomes an extremely convenient method for building coupled modeling when it comes to update/addition of new ocean/atmosphere modeling components. This is because it requires no significant knowledge of the internal structure of the individual models as well as software-engineering skill to modify to construct for model coupling. However one should eventually feel fluent in using/modifying the model to be able to produce the best results from the coupled model. The SCOAR hence allows users to spend more time in analyzing coupled model results without significant investment in time and efforts for technical modeling coupling.
• Development of SCOAR is motivated by the fact that climate models continue to have difficulties simulating the mean climate despite the significant improvement in numerical resolution and representation of physical processes. Some fundamental processes are poorly resolved in these models, including the SST variation associated with the ocean dynamics and the coupling of air-sea boundary layers. These presses are better resolved in the regional coupled models.
• SCOAR is a regionally coupled ocean-atmosphere model, developed by H. Seo as part of his Ph.D. thesis at the Scripps Institution of Oceanography, UCSD.
• SCOAR is originally coupled ROMS to RSM (SCOAR1).
• SCOAR2 (funded in part by ONR) couples ROMS to WRF model to study tropical intraseasonal oscillations in a tropical channel configuration (see the SCOAR2 presentation file).
• Currently two more coupling efforts are underway or planned:
  • Couple WRF to Process Study Ocean Modeling (PSOM, Dr. Amala Mahadevan at WHOI, http://vayu.whoi.edu/PSOM.html) to study the submesocale ocean-atmosphere interactions,
  • Couple Polar WRF to MIT-Ogcm for study of Arctic coupled air-sea-ice interaction.
  • See the publications and presentations using SCOAR1 and SCOAR2 can be found at
    • http://hseo.whoi.edu/cv
• Documentation for and SCOAR1 and SCOAR2 are found below: (thanks to Dr. Dian Putrasahan)

• The SCOAR1 and SCOAR2 are currently running on Scripps COMPAS, WHOI High Performance Computing Facility and NCAR Super Computing Facility,
  Note that RSM, WRF, ROMS are all community models, which can be run on a massively parallel computing facility of various architecture.
• SCOAR coupler can be complied in different machines and using different compilers with no major issues.

• Log:
  • Created June 10, 2007
  • Updated on December 10, 2011 for WRF-ROMS (SCOAR2)
  • Updated on June 10, 2012
  • Updated on June 10, 2013
  • Updated on November 10, 2013
  • Updated on May 27, 2014 to include interactive smoothing for US West Coast

The SCOAR model is currently running on Scripps COMPAS, WHOI High Performance Computing Facility and NCAR Super Computing Facility. Here are some more specific instructions on using the SCOAR2 model in each of these massively parallel clusters.
SCOAR2 (WRF-ROMS) at WHOI-Scylla
SCOAR (RSM-ROMS) at SIO-COMPAS
SCOAR (RSM-ROMS) at NCAR bluefire
SCOAR (RSM-ROMS) at UH-IPRC